1. Field of the Invention
The present invention is applied to the technical field where electrodes are formed by electroless plating on the surfaces of ceramic elements for ceramic electronic parts such as a dielectric resonator. More particularly, the invention relates to a holder for ceramic elements to be electroless plated, and a method of electroless plating utilizing this holder.
2. Description of the Related Art
Japanese Unexamined Patent Publication No. 1-234597, for example, describes that a plurality of ceramic elements for ceramic electronic parts are subjected to electroless plating in such a manner that they are loaded on a rotating barrel to form an electroless plated electrode of, for instance, copper on the surface of each of the ceramic elements.
Japanese Unexamined Patent Publication No. 8-134658 describes an electroless plating treatment in which a plurality of ceramic elements to be electroless plated are placed in a mesh bag and then loaded in a barrel.
Such methods of electroless plating utilizing a barrel as described in these publications often face a problem in that the ceramic elements to be electroless plated are liable to crack or to chip. In this connection, according to the method of electroless plating described in the latter Japanese Unexamined Patent Publication No. 8-134658, a plurality of ceramic elements to be electroless plated are placed in a mesh bag, and, therefore, such cracks or chipping of the ceramic elements can effectively be inhibited when the ceramic elements are placed into a barrel or are retrieved from the barrel.
The methods of electroless plating described in the aforementioned two publications cannot, however, avoid cracks or chipping of ceramic elements caused by a collision between the ceramic elements inside the barrel during the rotation of the barrel.
For the forgoing reasons, there is a need for a technique for avoiding the occurrence of such cracks and chipping as mentioned above in a method of electroless plating utilizing a plurality of ceramic elements. In particular, the formation of cracks and chipping in ceramic elements for a dielectric resonator must be strictly avoided.
Therefore, it is an object of the present invention to meet the above demands and to provide a holder for ceramic elements during electroless plating.
Another object of the present invention is to provide a method of electroless plating which is carried out utilizing such a holder for electroless plating as mentioned above.
The present invention is, in one aspect, directed to a holder for electroless plating to hold a plurality of ceramic elements for ceramic electronic parts during electroless plating treatment, in which each surface of the ceramic elements is to be electroless plated. To solve the above technical problems, the holder for electroless plating includes a plurality of cells to house each of the plurality of ceramic elements separately, and each of the cells has such a structure as to permit the flow communication of a plating solution into the cell.
This holder for electroless plating can particularly advantageously be applied when the ceramic elements are ceramic elements for a dielectric resonator.
In the holder for electroless plating according to the invention, the cells preferably form a contact which makes point contact or line contact with the ceramic elements.
Each of the cells preferably defines dimensions to give a clearance between each cell and each ceramic element, the clearance permitting each ceramic element to move inside the cell.
The holder for electroless plating according to the invention preferably has a configuration including a plurality of holder bodies each having an overall long shape and each forming a plurality of the cells distributed in the longitudinal direction, and a holder frame to hold the plurality of holder bodies arrayed two-dimensionally in such a manner that the longitudinal directions are oriented in the same direction.
In the aforementioned configuration, it is more preferable that each of the holder bodies includes at least two walls arranged in parallel with each other, and a plurality of pillar spacers to link the walls with each other at a plurality of points, and wherein each of the cells is defined by a portion interposed between the walls and surrounded by a plurality of the spacers.
It is further preferred that the plurality of holder bodies are arranged in such a manner that the walls of the individual holder bodies are arrayed two-dimensionally, and wherein the plurality of spacers to define each cell are constructed by two groups of spacers, one being located on one of first and second holder bodies adjacent to each other, and the other being located on the other of the adjacent first and second holder bodies, and wherein an opening is formed in each of the cells when the first and second holder bodies are separated from each other, the opening capable of receiving the ceramic element.
More preferably, gaps for the flow communication of the plating solution may be formed between the walls of the plurality of holder bodies arrayed two-dimensionally as described above.
The spacers are preferably circular in cross section, and the walls are preferably each provided with a height to reduce the contact area with the ceramic element.
The present invention is also directed to a method of electroless plating utilizing such a holder for electroless plating as mentioned above.
In this method of electroless plating, the following steps are conducted: providing the aforementioned holder for electroless plating, loading a ceramic element for ceramic electronic parts into a cell of the holder, and dipping the plurality of ceramic elements held by the holder in an electroless plating solution.
It is preferable that the holder is rotated or oscillated in the step of dipping the ceramic elements in the electroless plating solution.
For the purpose of illustrating the invention, there is shown in the drawings several forms which are presently preferred, it being understood, however, that the invention is not limited to the precise arrangements and instrumentalities shown.